Method of making incandescent lamps



NOV. 19, 1929. R uyows -METHOD OF MAKING INCANDESCENT LAMPS OriginalFiled July 27, 1925 2 Sheets-Sheet Inventor:

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w. R. BURRQWS METHOD OF MAKING INCANDESCENT LAMPS Original Filed July27, 1925 2 Sheets-Sheet 2 i a .inlfw PU n ma P W & mww H w UV b w iPatented Nov. 19, 1929 PATENT OFFICE WILLIAM R. Bunaows, or NEWARK, NEWJERSEY METHOD OF MAKING INCANDESCENI LAMPS Application filed July 27,1925, Serial The manufacture of incandescent lamps and many similardevices requires a large number of operations, man of which involve theheating and manipulating of glass tubing and cane. The standard practicein manufacturin incandescent lamps on a large scale is to perform eachof the operations in a separate department. For example, in making themount, some tubing, a pieceof glass rod 1 and some leading-in wires willbe welded to gether in the stem making department, then the anchors forholding the filament will be inserted in the glass rod by the hookinserting department and then the filament is placed on the anchors inthe Winding department. The finished mount is then sealed into the bulbin the sealing-in department, the unbased lamp exhausted in the exhaustdepartment, the base applied in the basing department, the lamp aged inthe aging department, inspected in the final inspection department andfinally packed in the packing department. The machines in these variousdepartments are of different capacities as several machines may berequired in one department to keep one machine in the next departmentsupplied. Each department is provided with enough machines to make allof its particular product that'is required by the entire factory.

By the standard practice a stock of parts in process of manufacture ismaintained between departments to take care of temporary excess ordeficiency of output of any department so that temporary trouble in onedepartment does not stop the factory. The output of each department isalso large enough to war-. rant the expense of inspection. In thestandard practice above outlined there is much handling of fragile partsbefore the lamp is assembled, causing breakage and loss, and much otherhandling of the assembled lamp. The stem maker takes the stem from thestem making machine and puts it in a tray. The tray islcarted to thenext department, where an operator takes the stem out of the tray, putsit in the anchor inserting machine, takes it out with the anchorsinserted, and puts it back in the'tray. In the next department the stemis takenout of the tray, the filament ap- No. 46,204. Renewed April 25,1929.

plied, and the mount put back in'the tray. At the sealing-in machine themount is taken out of one tray, the bulb out of another tray, and thenthe sealed-in lamp put back into a tray. From then on'the operation oftaking the lamp out of a tray and putting it back in the tray isperformed many times, first by the exhaust machine operator who takesthe lamp out of a tray, exhausts it and puts it back in the tray andthen by the exhaust inspector, by the basing operator, by the flashaging operator and by the final inspector after which the lamp is takenout of a tray and packed. Due to the stock of parts maintained betweendepartments, the lamp parts require on the average in a large factoryfrom onev half day to one day and a half to move from one department tothe next and while in stock accumulate dust and dirt which lowers thequality of the lamp. At every opera tion the lamp or some part of it istaken out of a tray and put back. This repeated handling, together withthe repeated transfers between departments, causes a Very considerablebreakage and in ur of the fragile parts such as the mount. A 1 lossesfrom every cause, commonly referred to as shrinkage, amount on theaverage in the best factories operated in accordance with the standardpractice above outlined to from 9% to 12%.

By my process incandescent lamps and similar devices may be manufacturedon a large scale with about one-half the shrinkage of the standardpractice above outlined, and the lamps produced will be on the averageof better quality. My invention increases the productivity of eachoperator about 30% and decreases the floor space required for a givenoutput about 30%. Well known glass working and lamp assembling machinesand devices may be used and in accordance with my invention are soarranged and coordinated that the glass stem of the mount passes fromthe stem making machine through the other machines and devices necessaryto the making of a complete lamp, the other parts of the lamp beingadded to it as it passes along and upon the termination of any operationupon a lamp art or of any step in its manufacture, particu arly prior tothe exhaust and sealing off of the lamp, the part is immediately anddirectly transferred to the succeeding machine or device where the nextoperation begins without delay. A lamp part removed from one of themachines or devices is transferred directly and immediately to thesucceeding device where it is placed or positioned Where work is to bedone upon it so that it is in readiness for the next operation. Wherethis transferring is done by hand, the operator in unloading a partfroma machine delivers it directly and as a part of the unloading operationto the place where the next operation is to be performed, therebyeliminating the repeated handling and the lost motion of the standardpractice.

My process is a continuous one in which the various steps necessary tothe manufacture of a lamp follow one another so directly and immediatelythat beginning with the stem-making the manufacture of a complete lampmay be completed in only a few minutes whereas the standard practiceheretofore followed is an intermittent process involving such long waitsbetween steps that to make a lamp requires days.

1 0st of the steps or separate operations necessary for lamp making,particularly those which involve heating or working of glass, are by myinvention carried out in direct sequence and with such slight delaybetween operations that any glass part which is once heated during thelamp making operations and thereby freed of moisture does not absorbmoisture or occlude gases before the lamp has been exhausted of the airin it. Keeping the glass hot during the making of v the lamp greatlyreduces the range of temperature changes to which it is subjected duringlamp making and lessens the breakage caused in the standard practice bythe repeated heating of cold glass from room temperature to thesoftening point, followed by its cooling down to room temperature again.

By my invention the glass is substantially gas free when the lamp issealed, as all or substantially all of it is heated so hot during themaking of the lamp that practically all the occluded gases are drivenout of it. Most of the glass in the mount and some of that in the bulbis heated to the plastic or welding temperature, and all of it is heateduntil it is substantially moisture and gas free, and after the glass isonce heated, it does not deteriorate by absorbing moisture or occludinggas before the air has been removed from the bulb and the bulbhermetically sealed.

The glass-working operations incident to the manufacture of the mountmay be car'- ried out on various well known types of machines anddevices for performing the successive steps of mount-making, thesemachines and devices being so coordinated in accordance with myinvention that within a short time which may be only a few minutes afterthe initial heating of any of the glass parts of the mount on thestem-making machine there arrives at the sealing-in machine a freshlymade substantially gas free mount. This mount is in excellent conditionto be put into the bulb, and is then, in accordance with my inventionand while still substantially gas and moisture free sealed into a hotsubstantially gas free bulb from which the air is immediately exhaustedwhile all of the glass of the lamp is still very hot and substantiallygas free.

The bulb into which the mount is sealed may be an ordinary bulb heatedthroughout to such a temperature at the sealing-in operation that it ispractically gas free. The sealing-in fires for welding the mount intothe neck of the bulb heat the bulb to some extent but by my inventionthe body of the bulb is subjected to additional heating while it is onthe sealing-in machine and prior to the closing down of the neck of thebulb on the edge of the flare. Of the total heating of the lamp on thesealing-in machine a good deal, in some cases about one-half, is due tothis additional or extra heating, the remainder being due to thesealing-in fires. The heating not only drives the occluded gases out ofthe glass of the bulb, but expels a great deal of those gases by causingthe air in the bulb mingled with the gases driven out of the glass, toexpand and most of it escapes freely while the neck of the bulb is offull diameter and neither the expelled gases nor other deleterious gaseshave .an

opportunity to re-enter the bulb. If the bulb with but with most bulbsthe additional heating isnccessary in order to get a high quality lamp.

My invention may be practiced to best advantage when' the variousmachines and devices used are placed adjacent to each other with thedelivery positionof one in such relation to the loading position of thenext that the lamp part can be transferred from any one to the nextdirectly and with a minimum of lost motion. This transfer may be madeautomatically or by an operator and the machines and devices are sotimed and synchronized that as anyone delivers a part the next is readyto take that part.

The mount, from the time the glass parts of it are first positioned inthe stem-making machine, progresses step by step through each machineand from one machine or operation to the next, each step bringing itthat much nearer to a finished lamp and all the steps. particularlythose between machines or operations. being taken as directly and withas little delay as possible.

During the manufacture of lamps on a large scale there are for eachcomplete lamp pm duced a certain number of .parts in process ofmanufacture and in various stages of completion. By the standardpractice there are a great number of parts in process of manufacture,most of which are in stock between departments and a great many traysare required to store and transport these parts, but by my inventiononly a few parts are in process and'the only trays needed are those forcarrying and storing bulbs. For example, a factory having an output ofabout 30,000 lamps per day which follows the standard practice will havein process-of manufacture lamp parts of a value of about $14,000 andwill use about 3200 trays for bulbs and about 1100 trays for mounts. Afactory having the same output, but operated in accordance with myinvention, will have in process of manufacture such a small number ofparts that theirvalue is only about $1,500, and will have only 1000trays, which are used for storing and handling bulbs.

By my continuous process the uality of the lamp is improved, shrinkageis essened and much better and quicker service to the customer may begiven as finished lamps of any particular type ordered are obtainedwithin a very short time after manufacture begins.

By the standard practice a number of days is required to manufactureeven a very small.

number of lamps owing to the length of time necessary for the variousparts required for the order to move from one department to the next.

Although my improved process of manufacturing lamps may be carried outin many difierent Ways and with many different types of machines, Iprefer to use an apparatus or machine which I have invented and in whichthe various devices or mechanisms for making the lamp parts and forassembling them into a complete lamp are tied together or interlocked,either electrically or mechanically, to compel all of the mechanisms tooperate in synchronism and in definite time relation one to the other.In the machine which I prefer various lamp-making mechanisms aremechanically interlocked through a common actuating or driving means,which in efiect, ties all of the mechanisms together and compels all ofthem to operate in a predetermined and unvarying relation. Thesemechanisms I or devices are mounted adjacent to each other with thedelivery position of each one in such a relation to the loading positionof the next that a'lamppart can be transferred from one mechanism to thenext with minimum move merit and delay. I prefer to mount all of thesemechanisms on a common base or table and to drive them from a commonshaft carried by the table and in this way, I obtain a self-containedportable unitary lamp-making supply for the burners and which can easilybe moved when desired.

, The common driving shaft interlocks all of the mechanisms and keepsthem in synchronism preferably by being connected to them by gearing andwhere the various mechanisms are of the step by step type a convenientway is to drive the common driving shaft through intermittent gearing,so that for each step of the driving shaft all of the mechanismsconnected to it make'one step. In this manner I provide. a unitarycomplete machine to which the glass parts of the mount maybe supplied atone end, various other parts of the lamp being added to the mount as itprogresses step by step through the various mechanisms and from onemechanism or operation to the next, all these parts being combined toform the finished lamp, which is delivered at the other end. The variousmecln anisms are so proportioned that as each one delivers a lamp partupon which it has been operating the next one is ready to receive thatpart and to begin the next operation.

To supply the additional heattothebulbson the sealing-in machine duringthe sealing-in operation, I prefer to use auxiliary burners mounted toheat the body of the bulb and so distributed that the bulb is verythoroughly heated before it reaches the final sealing-in position wherethe neck collapses. In this way I am able to deliver to the exhaustmachine a sealed-in lamp hot enough to be exhausted and thereby Ieliminate the oven which has heretofore been considered an essential andnecessary part of an exhaust machine.

The exhaust mechanism is preferably so arranged that it can be usedeither to ex.- haust vacuum lamps or to exhaust lamps and then fill themwith some inert gas such as argon to make gas filled lamps with the.result that either vacuum or gas filled lamps can be made on myselfcontained portable lamp-making machine with a minimum delay andshrinkage, each lamp being completed within a short time after itsmanufacture is begun.

For a better understanding of my invention reference may be had to theaccompanying drawings in which merely for purposes of illustration, Ihave shown one form of machine embodying my invention and by means ofwhich my improved method can be practiced to advantage. In theparticular machine illustrated Figure 1 is a plan view of the machine;Fig.2 is a side view and elevation with some parts broken away better toshow the structure; Fig. 3 is a longitudinal section immediately belowthe top of the table to show the arrangement of the driving mechanism;Fig. 4 is a vertical section along the line 4.4 of Fig. 3, showing thegear for driving the main and auxiliary shafts; Fig. 5 is a view inperspective showing the various steps of assembling the lamp and theauxiliary burners for imparting additional heat tothe lamp during thesealing- 'in operation; Fig. 6 is a perspective view of a part of theautomatic tipping olf device; Fig. 7 is a perspective view of means forremoving the waste ends of the exhaust tubes from the exhaust machine;and Fig. 8 is a diagram showing the connections for the flash agingmachine.

Merely to explain one way in which my invention may be practiced, I haveillustrated the manufacture of an incandescent lamp of the tipless type,best illustrated in Fig. 5. The glass bulb 10 of this lamp contains amount made up of a glass stem tube or flare 11 and a glass rod or hub 12joined at one end to the stem tube and having atthe other end anenlargement or button 13 in which are embedded a number of tungsten ormolybdenum anchors 11 to carry the -fila ment 15 which is preferablycoiled and arranged in the form of a ring. The ends of .the filament areclamped or secured to leading-in wires 16 hermetically sealed into theglass stem tube 11. This tipless lamp is exhausted through an exhausttube 17 which extends up into the stem tube 11. This particular type oflamp and stem is illustrated more in detail in the United States Patentsto Mitchell and White Nos. 1,423,956 and 1,423,957, July 25, 1922.

In the particular type of machine illustrated in the drawing the variousdevices for making the lamp parts and assembling them are mounted upon acommon portable base such as a table 18 and are all driven by motor 19through common driving means which interlocks the mechanisms andcomprises spur gearing 20, a continuously rotating auxiliary drivingshaft 21, intermittent gearing 22, and an intermittently moving maindriving shaft 23 driven step by step by the intermittent gearing. Thevarious lamp-making devices and mechanisms mounted on the table 18 aredriven in definite relation to one another and kept in step andsynchronism by the driving shaft 23.

In the particular machine illustrated the manufacture of the mountbegins on the stemmaking machines A,.on which theoperator at station -Vassembles the flare or stem tube 11 the glass rod or cane to form thehub 12 the exhaust tube 17 and the leading-in wires 16. This particularstem-making machine is driven from the intermittently actuated drivingshaft 23 by gearing, such as the spiral gears 24, which impart the stepby step movement of the driving shaft to a spider 25 provided with fiveheads 26 which hold the parts of the stem in proper relation. Theintermittent movement of the spider brings each head in successionwithin range of the burners or fires 27 and holds it stationary untilthe adjoining ends of the stem tubing, the exhaust tube, and the cane orhub are nearly at the melting point, whereupon all of these parts arepressed together and the leading-1n wires embedded in the glass bypinching jaws 28 mounted on the head and actuated through a push rod 29which in turn is actuated by a lifter 30 mounted in the table 18 anddriven by a cam 31 on the continuously running shaft 21. The head thenmoves to the next position where a burner 32 directs a pointed flameupon the stem between the leading-in wires and air under pressure isdelivered through a jet 33 to the interior of the-exhaust tube 17 toblow a hole through the solid mass of hot glass formed by the pinchingjaws. Many other forms of stem-making machines can be used. The form ofstem-making machine illustrated is suitable for the practice of myinvention and is described more in detail in United States patent toMitchell and White, No. 1,423,957, July 25, 1922. 4

I may to advantage arrange the machine as shown in U. S. Patent 860,977,Howell and Burrows, July 23, 1907, so that the operator loads it withshort pieces of stem tubing which are then flared on the machine beforethe leading-in wires are placed in position thereby eliminating thepreliminary opera tion of making flares.

The stem making operation heats the adjoining ends of the stem tube, ofthe exhaust tube and of the hub until they are plastic and thereforefree from gases and water vapor. The stem with these parts still hot istransferred by the next operator at station W to the hook insertingmachine B which makes the button 13 and inserts the anchors 14. Beforethe stems are put into the hook inserting machine they may be annealedby an annealer consisting essentially of a horizontally rotatable table3i provided with pockets or holders 35 in which the stems may be placedto be heated by auxiliary gas burners if desired, although ordinarilysuch extra heating is not required.

The hook inserting machine is a simple and well known form suitable forstems having only one button and one set of anchors, although similarmachines are well known which are constructed to form two buttons andinsert two sets of anchors. Either type of machine may be used,depending upon the type of lamp which is being made. The particular hookinserting machine B which is illustrated in the drawing isintermittently driven by the drive shaft 23 through spiral gears 36which are connected to a three arm spider 37 having a rotatable stemcarrying head 38 onthe free end of each arm. As each head comes to theloading position infront of the operator. at station TV a stem from thestem making machine A is placed in the head. This loaded head is thenautomatically carried to the next position, where the upper or free endof the hub 12 is heated almost to the cally. The head then moves to thenext position where the anchors are inserted one at a time by an anchorinserting mechanism 41, such/as that illustrated in the U.- S. patent,

Frech and F agan, 1,220,836, March 27 1917.

A particular point on the button 13 is heated by a burner 42 until it isplastic and then the anchor is automatically'thrust into the softenedglass and thereby embedded in it. To present the different points on thebutton to the burner 42 and to the hook inserting mechanism each head isautomatically rotated step by step at the hook inserting position. Forsimplicity I have illustrated a lamp provided with only three anchorsset 90 apart. To insert these anchors I rotate the stem holding head atthe hook inserting position b some intermittently acting mechanism sucas a four tooth ratchet wheel 43 controlled by ,a locking pawl 44mounted on the spider arm and a driving pawl 45 mounted on the outer endof a swinging arm 46 which is carried on a shaft coaxial with the headwhen it is in hook inserting position and which is driven automaticallyin any suitable way. As the head moves into and out of book insertingposition the ratchet wheel 43 comes within and passes. out of range ofthe driving pawl 45. v t V The hook insertingmechanism illustrated inthe Frech and Fagan U. S. Patent 1,220,836 is operated from a rock shaftwhich is rocked by a handle. In the particular machine I haveillustrated this rock shaft of the rocked by a corresponding arm 47moved by a rod 48 actuated automaticallyby any suitable mechanism. Thenecessary movements can be given to the parts of the hook insertingmachine by man forms of automatic mechanism. Merely or the purposes ofillustration I have shown an actuating mechanism comprising a cam shaft49 which makes one revolution while the spider 37 is statlonary and thenis stationary while the spider is stand idle while the shifting to thenext position.

This relative movement of the cam shaft 49 and of the spider may beobtained in many different ways, but merel for purposes of 11- sets ofteeth each equal in num or to the teeth on the pinion 50 and two blankspaces between the sets of teeth, each blank space being long enough topermit the pinion 50 to step. J

The button presser 40 1s reciprocated once for each revolution of thecam shaft 49 spider 37 is shifting one through a bell crank lever 53actuated by a cam 54 on the cam shaft. The stem carrying head 38 whilein hook inserting position is intermittently rotated, one completerevolutionmoving the arm 47 to insert an anchor through a rocking lever56 and a cam 57 having three points apart to cause the anchor insertingmechanism to insert three anchors and then skip one for each. revolutionof the cam shaft.

It may be considered desirable to form on the ends of the anchors aclosed 100 or hook instead of the open hook formed by t e shapesillustrated in the Frech and Fagan U. S.- Patent 1,220,626, and in suchcases I may close the open hooks by hand when the operator puts.-

the filament in the anchors, or I may close the books on the machine bysome automatic means, such as a rotatable bender 58 which has projectingfrom its end one pin concentric with its axis to form or support theloop of the hook and another in eccentric to the axis to carry the freeen of the hookaround the first pm when the bender is rotated at theproper time by gearing '59 actuated in inserting mechanism. The bender58 is carried on an arm which is swung about the shaft of the large gearof the gearing 59 as an. axis by a suitable cam to bring the bender upinto operative relation to the anchor to bend the hook and then to dropit. back out of the way.

After the anchors are inserted the head .38 carrying'the stem returns tothe loading position in front of the operator, who removes the stem fromthe head and replaces it with a fresh one. He then fastens the filamentto the leading-in wires by some suitable means such as the pinchers 60or an electric welder hook inserting mechanism is automatically P p timerelation to the Test of the anchor mounted in the same position as thepinchers. i

The mount is now completed. .It maybe, if desired, placed in a rotatableholder 61 so as to be convenient for the sealing-in and eghau'stoperator at position X.

. The mounts are sealed into the bulbs by a sealing-in machine Cintermittently driven by the drive shaft 23 through spiral'gears 62which drive a spider 63 provided with rotattion is rotated with the neckof the bulb within range of the scaling-in fires 65.

The sealing-in fires heat the glass at the various positions. and at thefinal position weld the mount into the neck of the bulb. The bulb issteadied and the surplus neck pulled off by a pivoted fork 66. Each headmay be rotated by a friction Wheel 67 which engages friction wheels 68when the spider is stationary the Wheels 68 being driven by gearing 69from the continuously running shaft 21. Each head has a verticallymovable tubular mount carrier 70 which holds the mount and which may beconstructed in well known ways for instance, as shown in United Statespatentto James E. Marshall, No. 1,475,192, November 27,1923.

This mount carrier is lowered at the loading position to permit easyinsertion of the mount, and is automatically raised at the otherpositions as its lower end rides up on a circular cam track 71 whichextends-under all the positions of the heads except the loadingposition. After the head leaves the final position the lower end of themount 70 runs off the end of the cam track 71 into a control fork 72which takes hold of it and lowers the mount carrierthereby leaving thesealrd in lamp free. The control fork is actuated by a rock lever 7 3from a cam 74 on the shaft 21.

An im ortant feature of my invention is the use 0 a substantially gasfree bulb. The mount arrives at the scaling in machine with all of itsglass parts substantially free from strains and from water vapor andoccluded gas, due to the short intervals between the various stem makingoperations and the quick transfer of the stem to the sealing-in machine.I may use cold bulbs made and stored in the usual manner by subjectingthe bulbs and the other glass parts to a very thorough heating on thesealing-in machine. If the bulb is substantially free from gases andwater vapor the heatingcaused by the sealing-in operation during which azone on the neck of the bulb is heated until the glass is plastic willbe sufficient, but for bulbs of the usual sizes and quality additionalheat is necessary to of lamp.

In accordance with my invention all parts of the bulb are verythoroughly heated during the sealing in operation and before the neck ofthe bulb collapses upon the flare of the mount, thereby causing theoccluded gases and water vapor to be driven out of the walls of the bulband to mingle with the air, in the bulb. This air being strongly heated,expands and much of it passes out of the bulb while the neck is of fullsize so that the escape of the heated air with its entrapped gases andwater vapor is practically unobstructed. By

the time the bulb reaches the final position where the final fires causethe neck to collapse upon the flare and be welded to it, the.

produce the highest quality r bulb contains only attenuated heated airand the walls are practically free from gases and water vapor. Inaddition the intensely heated air in the bulb heats the stem and hub ofthe mount, thereby not only maintaining the temperature of the glassparts of the mount but raising their temperature until they areextremely hot. This additional heat may be supplied in various ways, butI prefer to use auxiliary burners such as the burners 75 best shown inFigure 5 so arranged that in each of four positions and before its neckhas collapsed the bulbis subjected to a well distributed hot flame whichheats the body of the bulb very thoroughly. In addition, in the finalposition, I further heat the bulb by means of an auxiliary burner 76which directs its flame upon that part of the neck between the zonerendered plastic by the sealing-in fires and the body of the bulb. A

very complete and uniform heating of all obtained. The auxiliary burners75 and 76 may be supported in any convenient way. as for example. bymeans of the supply pipe 77. By means of these auxiliary burners I raisethe temperature of all of the glass parts of th; lamp to about 310 C.when the lamp is finally sealed in at the final position and at thistemperature all of the glass is practically free from gases and watervapor. Without the auxiliary burners enough water vapor might remain inthe glass to injure the quality of the lamps.

Thesealed in lamps while still extremely hot are taken from thesealing-in machine by the operator at station X. The hot lamps arehandled by tongs or in some similar manner, and are transferred directlyand as quickly as possible to the exhaust machine D where the air isquickly exhausted from the lamp so that it is free from air, watervapor, and injurious gases. If the lamp is a vacuum lamp it is thensealed off or if it is a gas filled lamp is exhausted, filled with someinert gas, such as argon, and then hermetically sealed. In either casethe deleterious gases'and water vapor are driven out of the glass andremoved from the lamp before the bulb is sealed Off. No oven or similarheating means on the exhaust machine is required as by my invention thelamps arrive at the exhaust machine hot enough for exhaust. This is amarked advantage and causes a marked saving in cost of'machinery, andreduces the shrinkage due to heating up sealed-in lamps which have become cold.

The particular type of exhaust machine D which I prefer to use is drivenby the drive radial and circumferential spacing as the ports in thevalve so as to register with them. 'As shown in Figure 2,'each port inthe valve is connected to a tube holder 81 for holding the exhaust tubeof the lamp. The particular machine illustrated in the drawing issuitable for manufacturing gas filled lamps and the valve is providedwith twelve ports so arranged with reference to'nine similar ports inthe valve seat that as the valve makes one revolution any one portregisters-in succession with the nine ports in the valve seatand thenpasses through three idle positions where it does not register with anyports at all. These idle positions provide one unloading and two loadingpositions.

The valve 79 rotates step by step in a counter-clockwise direction, andthe hot'lanip direct from the sealing-in machine C is placed in'theexhaust machine by inserting the exhaust tube 17 in an exhaust tubeholder 81 at one of the idle positions 7' and 70. If the flat valve 7 9is moved intermittently and step by step from the driving shaft 23 thelamp eventually comes to the first active position L where it isconnected to the exhaust pump 82 and in this position the air isexhausted from the bulb. By the next step the valve carries the lamp tothe second active position m where the lamp is connected to a leakdetector 83 or some similar device for showing whether the lamp leaks.The next step brings the lamp to the third active position n where it isfilled with nitrogen from a nitrogen supply manifold 84.

At the next four positions 0, p, g, and 1* it is connected alternatelyto the pump and to the nitrogen supply and finally inthe eighth activeposition s to the pump 82. By this time the lamp has been thoroughlywashed out with nitrogen, and all of the water vapor and deleteriousgases driven out of the lamp have been completely removed. The next stepcarries it to the ninth active position If Where it receives a chargeof'argon through an argon supply pipe 85 and at the same time theexhaust tube is heated to some extent by -a preliminary torch 86. Inthis figure the lamps connected to the pump are marked P, thoseconnected to the nitrogen supply are marked N and that connected to theargon is marked Ar.

The lamp is now ready to be sealed off and at the next step it comes tothe idle position a where its ports is on a blank part of the with aweight 89 engages the bulb in the sealing off position and raises it ashort distance when the exhaust tube is melted at the contraction.

The tipping off torch 87 and lifting fork 88 are raised and loweredbodily by some automatic mechanism. They may, for exam- After the lamphas been sealed off and lifted by the lifting fork 88 from the stub ofthe exhaust tube the valve 79 moves to the next idle position j andduring this movement the stub of the exhaust tube is caught by astationary finger 92 and pulled out of the tube holder 81 as indicatedin Figure 7. The thick walled rubber tubing used in the tube holder isso mounted as to be flexible and yielding enough to permit this actionto take place. lVhen-the machine is to be used for making vacuum lampsthe ports in the valve seat may be connected to the pumps in variousways, as will be obvious to those skilled in the art. For instance, theports at positions 8 and 27 may be connected to the final pump and thoseat position a, p, and r to a source of hot dry air, instead of nitrogen,to give the lamps a dry air wash during exhaust; or the .ports atpositions at anclo may be connected to the preliminary pump and those atp and g to the final, the tipping off torch being placed at position 9and either some provision made for carrying the sealed off lamps to thebasing operator at station X or the stations Y and Z placed in the sameside of the table as the pump 84 to enable the operator at station Y totake the lamps sealed off at position 9. Suitable connections of theports to the pumps for exhausting the lamps are disclosed in U. S.patent to Massey, 996.936, July 4,

1911, and in my U. S. Patent, 1,013,124, Jan- I uary 2, 1912.

The sealed 0E lamp is taken off by the operator at station Y who appliesto it a metal base lined with soft cement and places the leading-inwires properly on the base. The lamp and base is then placed in thebasing machine E which is driven through spiral gears 93 from' the driveshaft 23 and consists essentially of a horizontal wheel 9% having aniron rim 95 provided with a series of pockets 96 which receive the basesof the lamps. Each pocket is heated during its travel to bake the cementand is then cooled.

This may be done in many ways. In the machine shown the pockets arecarried by the intermittent rotation of the rim between twosemi-circular concentric gas burners 97 which are supported by thesupply pipes 98 and heat each pocket 96 and the base in it to bake thecement which fastens the base to the bulb. In this particular machineeach pocket is within range of. the burners for 8 positions and then forthe next 6 positions it is between two concentric air pipes 99 which arecarried by the supply pipe 100 and direct cooling air upon the pocket.By the time the lamp has completed one circuit of the basing machine andreturned to the loading position, the base has been baked on and thelamp is ready to be removed. The lamps are held with the bases in thesockets by some suitable holders such as the vertically movable holders101 provided with springs 102 to yieldingly hold the bases in thesockets and the bulbs in the bases until the cement hardens.

The based lamp is removed from the basing machine, the leading-in wiressoldered to the base with a soldering torch 103, and the lamp thenplaced in the flash aging machine F which automatically passes certainamounts of current for certain lengths of time through the filament ofthe lamp to age it. The particular type of flash aging machine shown isa rotary machine driven through gears 104 from the drive shaft 23 andcomprises an intermittently rotating table 105 provided with sockets 106connected as shown diagrammatically in Fig. 8 to a supply circuit. Theconnections are such that as the table 105 rotates in clockwisedirection the lamp is connected in succession through the resistances107, 108, 109, 110, so proportioned that successively amounts of currentpass through the filament. As the lamp completes the circuit and returnsto its initial position the operator at stationZ whose position issomewhat further to the left than is shown in Fig. 1 removes it from theflash aging machine, inspects it, and packs it whereupon it is ready tobe put into stock.

All of the lamp making devices from A to F are driven by common driveshaft 23 which keeps them all in step and synchronism. I may so time themachine that the stem making machine A and the hook inserting machine Brun about 10% faster than the remainder of the machine to allow for someslight losses in the mount making operations. The sealing-in machine C,exhaust machine D and basing machine E, and aging machine F, may toadvantage be timed to move from one position to the next every 15seconds so tlliltjf no losses are incurred the output of each machine isfour lamps per minute.

The operation of my machine will be evigreater dent from the abovedescription. All of the operations are conducted in a definite and fixedsynchronism and time relation to the other operations and all lamp partsare transferred directly and immediately from one operation to the next.No stock accumulates between machines or operations and all operationsand transfers are conducted with such speed that the glass in theinterior of the lamp does not become contaminated by water vapor andoccluded gases because of the speed with which the lamp has beenassembled and the bulb has been sealed. Even after the lamps have beenwashed out with nitrogen on the exhaust machine D, filled with argon andsealed off, they are still too hot to handle with bare hands, while thetemperature of all of the glass at the time the lamps are firstconnected to the pump 84 is usually in the neighborhood of 300 C.

The machine is a portable self contained unit capable of performing. allthe operations necessary to assemble a finished lamp. The

pumps and similar parts may be mounted on the machine, as on a shelf orangle iron 110, and the table may be provided with castors to make itreadily movable. The operators are so close together and all operationsare conducted with so little delay between them that if the finishedlamps are defective in any respect the trouble is immediately locatedand remedied before more than a few defective lamps are made.

I have described my improved process as applied to the manufacture ofincandescent electric lamps but my invention is equally valuable in themanufacture of any similar device particularly one which has a glassbulb with a mount or interior structure con taining glass.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

'1. The process of making an incandescent lamp or similar article whichcomprises joining a glass stem to metal wires by fusing parts of thestem and thereby heating all the glass until it is substantiallymoisture and gas free, securing a filament to said wires before theglass becomes cool enough to accumulate a harmful amount of moisturewhereby a substantially moisture free mount is obtained, sealing saidmount while still substantially moisture free into a bulb, heating thebulb hot enough to render it substantially moisture free, removing theair from the sealed in bulb while it is still hot, and sealing off thebulb while free from air.

2. The process of making an incandescent lamp or similar sealed devicecontaining a filament supported by wires embedded in a glass stem whichcomprises heating part of the glass stem until it is plastic and therebyheating the remainder of the stem to a temperature such that all theglass of the stem is substantially moisture free, embedding wires in theplastic glass, mounting a filament on the embedded wires while the glassof the stem is still hot enough to be substantially free from moisture,sealing the freshly made mount while still hot enough to besubstantially moisture 'free into a glass bulb by welding by fusionanother part of the glass stem to the neck of-;sai d bulb, heating saidbulb while it is filled with air to raise in all the glass of said bulbto a temperature at which it is substantially moisture free, exhaustingthe air from said sealed in bulb while it is still hot, and hermeticallysealing off the bulb while free from air.

3. The process which comprises heating one end of a glass stem tube toproduce a hot plastic mass of glass and embedding wires in said hotplastic mass of glass, mounting a filament on said wires while said massis so hot that it is substantially moisture free, sealing the other endof said stem tube into the neck of a glass bulb by fusion while saidglass'mass is still so hot as to be substantially moisture .free,imparting to said bulb prior to and during the sealing-in of the stemand while the bulb is open sufiicient heat additional to that used forscaling in to bring all of the bulb to a high temperature and render itmoisture and gas free, exhausting the air from said sealed in bulbwithout further heating and while it is still hot from the sealingin,and sealing off the bulb while free from air h tssau ra sas an a o ywiilmurn. BURBOWS.

'cniiriricarn or CORRECT-ION. 7

Patent No. 1,736,767. 7 Granted November 19, 1929, to

' WILLIAM R. minnows.

It is hereby certified thatthe above numbered patent a erroneouslyissued to the inventor said "Burrows" whereas said patent shouldhavebeen issued to "General Electric Company, a Corporation ofNew-York", said corporation being assignee of the entire interest insaid invention, as shown by the records of assignments in this office:In the heading to the drawings, sheets 1 and 2, strike out line 3, andinsert instead "Original filed June 14, 1922"; In the heading to theprinted specification, strike out line 4,application filed clause, andinsert "Original, application filed June 14, 1922, Serial No. 568,166.Divided and this application filed July 27, 1925, Serial No. 46,204.RenewedrApril 25, 1929"; and that the said'Letters Patent should be readwith these corrections therein that the same may conform to the recordof' the case in the Patent Off ice.

Signed and sealed this 14th day of January, A. D. 1930'.

. M. J. Moore, (Seal) 7 Acting Commissioner of Patents.

